Drift indicator



p 1, 95 E. G. PEEBLES 2,901,835

' DRIFT INDICATOR Filed Aug. 1, 1955 FIG- ,4'13-2 INVENTOR. [0644 6. @2245;

irrae/vi i D I I A O I Edgar G. Peebl'es, Arcadia, Calif. Application August 1, 19 55, Serial No. 525,472

2 Claims. C1. as-205.5

This invention relates generally to inclinometers, and more particularly to such devices which are known in the art as drift recorders and which are used to measure the deviation from the vertical of a well, or hole, drilled in the earth to a relatively great depth.

It is the principal object of this invention to provide a novel form of drift indicator which is adapted to be lowered or dropped through a drill string to seat in the lower end thereof in coaxial alignment therewith, and wherein said drift recorder is adapted to be actuated for recording the inclination by speeding up the circulating pumps to increase the velocity of the fluid downwardly through the drill string.

A preferred embodiment of the invention is described in the following detailed specification, and illustrated by way of example in the accompanying drawings, wherein:

Fig. 1 shows a longitudinal section of a device embodying the principles of the invention.

Fig. 2 shows a similar view to that shown in Fig. l, but showing the device after it has been actuated.

Referring now to the drawings wherein similar reference numerals are used to denote the same elements throughout the various views shown, the drift indicator generally comprises a tubular housing 11, having a pendulum 12 supported therein in such manner that it is capable of assuming an inclined position relative to the axis of the housing throughout the full 360 of orientation. The pendulum 12 is provided with a pointed stylus 13 at its upper end adapted to mark a record blank 14 mounted on a piston 15, slidably received in the housing 11 above the pendulum 12.

The piston 15 is fixedly attached to a piston rod 16 which extends upwardly through the closed upper end 17 of the housing 11 and terminates in an enlarged head 18. A suitable O-ring 19 provides sealing engagement between the piston rod 16 and the housing end 17. A spring 20 surrounds the piston rod 16 and is confined between the enlarged head 18 and the housing end 17 to normally urge the piston 15 to its uppermost position relative to the housing 11 in the manner illustrated in Fig. 1.

The lower end of the housing 11 is closed by a plug 21 threaded therein. The plug 21 has a central bore 22 extending therethrough and is provided with a depending tubular extension 23. A tubular flexible diaphragm 24 of rubber or similar material is bonded or otherwise fastened to the tubular extension 23 in sealing engagement therewith. A plug 25 is received in, and closes the lower end of the diaphragm 24. The diaphragm 24 is clamped thereto as by the wire indicated at 26. The interior of the housing 11 is filled with oil or other suitable fluid.

A shoe 27 is fixed to the lower end of the housing 11 and extends downwardly therefrom to protect the diaphragm 24. The shoe 27 is provided with a plurality of ports 28 to permit well fluid to enter therein and exert pressure on the diaphragm 24 to equalize the pressure within and without the housing 11.

The lower end of the shoe 27 is semispherical as indi- U i d States Patefl 2 cated at 29 to cooperate with a suitable seat 30 inserted in a drill string 31 to center the lower end of the drift indicator 1'0 therein. The seat '30 is provided with-a plurality of longitudinal passageways 32 to permit the well fluid to pass therethrough when the drift-indicator 10 is seated thereon. A plurality of bow springs 33 are fixed to the housing 11 adjacent the upper end thereof at equally spaced points therearound to center the' upper end ofth'e 'dr'iftindicator 10 within .the'drill stringfili Four strap-like. spider members 34 arefixed -torthe upper end of the housing 11 at equally spaced points therearound. The spider members 34 extend upwardly around the head 18, then converge inwardly together and are fixed to each other at the axis of the drift indicator 10. A spear point 35 is connected to the spider members 34 to permit retrieving of the drift indicator 10 after the recording has been made.

In the use of the device, the drift indicator 10 is dropped or lowered through the drill string 31 until the lower end 29 thereof seats on the seat 30. The mud circulating pumps are then speeded up so that the increased downward fluid velocity impinging on the head 18 will force the piston 15 downwardly against the pressure of the spring 20 until the stylus 13 makes an impression on the record blank 14, in the manner illustrated in Fig. 2. If a multiple recording is desired, it is merely necessary to stop, or decrease the speed of the mud circulating pumps, and the device will reset itself, whereby again increasing the speed of the pumps will produce another recording.

While I have shown and described the preferred form of the invention, it is obvious that various changes may be made in its construction by those skilled in the art, without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A drift indicator comprising a tubular housing to be lowered within a drill string in coaxial alignment therewith and having a lower end shoe portion adapted to seat on a collar within the drill string, a flexible diaphragm within said shoe portion and closing the lower end of said tubular housing, said lower end shoe portion having a plurality of radial ports to permit well fluid to enter therein and exert pressure on said diaphragm, a pendulum device suspended from and within said housing, a pointed stylus on the upper end of said pendulum, a piston in said housing above said pendulum, a record blank fixed to the underside of said piston, a piston rod fixed to said piston and extending upwardly through the upper end of said housing, sealing means between said piston rod and said upper end of said housing to prevent fluid communication therebetween while allowing limited axial movement of said piston in said housing, said housing being filled wth a liquid, an enlarged head connected externallyof said housing to said piston rod, whereby an increase in the velocity of downwardly flowing fluid impinging on said head will cause said piston to move downwardly forcing fluid toward said flexible diaphragm and bringing said record blank into contact with said stylus, and spring means between said enlarged head and the upper end of said housing urging said piston upwardly from its lowermost position upon a decrease in velocity of the downwardly flowing fluid.

2. A drift indicator comprising a tubular housing to be lowered within a drill string in coaxial alignment therewith and having a lower end shoe portion adapted to seat on a collar within the drill string, a flexible diaphragm within said shoe portion and closing the lower end of said tubular housing, said lower end shoe portion having a plurality of radial ports to permit well fluid to enter therein and exert pressure on said diaphragm, a pendulum r 3 device suspended from and within said housing, a pointed stylus, on the upper end of said pendulum, a piston in said housing above said pendulum, a record blank fixed to the underside of said piston, a piston rod fixed to said piston and extending upwardly through the upper end of said housing, sealing'means between said piston rod and upper end of said housing to prevent fluid communication therebetween while allowing limited axial movement of said piston in sad housing, said housingbeing filled wth a liquid, an enlarged head connected eXternally of, said housing to said piston rod, and a coiled spring circumvallating said piston rod between said upper end of said housing and the underside of said enlarged head and'urging said head upward, whereby an increase in the velocity ofthe downwardly flowing fluid impinging on 4 said head will cause said piston to move downwardly and bring said record blank into contact with said stylus.

References Cited in the file of this patent UNITED STATES PATENTS 

